Method and device for severing and mechanically removing yarn ends in circular knitting machines for fine knitted goods,in particular stockings



Jan. 7, 19769 E. LUZZATTO 3,420,076

METHOD AND DEVICE FOR SEVERING AND MECHANICALLY REMOVING YARN ENDS IN CIRCULAR KNITTING MACHINES FOR FINE KNITTED I GOODS. IN PARTICULAR STOCKINGS Filed Nov. {5, 1966 v 7 Sheet of 2 E ffare L uzztflk BY 4 flab/m2 i I INVENTOR.

Jan. 7, 1969 E. LUZZATTO 3,420,076

METHOD AND DEVICE FOR SEVERING AND MECHANICALLY REMOVING YARN ENDS IN CIRCULAR KNITTING MACHINES FOR FINE KNITTED GOODS. IN PARTICULAR STOCKINGS Filed Nov. 5, 1966 Sheet 2 of 2 $1] INVENTOR.

Ettore Luz-J. 4J1- United States Patent Office Patented Jan. 7, 1969 11,036/65 US. Cl. 66140 13 Claims Int. Cl. D041) 35/32 ABSTRACT OF THE DISCLOSURE A stream of pressurized gas is directed by a first nozzle onto inactive yarn ends, which extend from a yarn feed station across the top of a dial plate in a circular knitting machine, to urge the yarns into frictional tangential engagement with a portion only of the periphery of a foraminous drum that rotates above the dial plate adjacent the inlet of a conventional suction device. The suction device is positioned opposite the first nozzle and the point where the yarns initially engage the drum. Compressed air is also blown radially outwardly from the interior of the drum through one or more nozzles that are directed at the inlet to the suction device, so that the yarns are disengaged from the drum and blown into the suction device approximately 180 from the point they initially engage the drum. Instead of the drum, a travelling, foraminous belt may be used.

It is well known that in circular knitting machines for fine knitted goods, and in particular in machines for the manufacture of ladies stockings and the like, operating conditions lead to the formation of numerous free yarn ends, which must be clipped adjacent the stitch formations and subsequently removed from the knitting zone.

Various systems and devices have been proposed to avoid severing and removing said yarn ends by hand.

In known devices, cut yarn ends are generally removed by suction. The yarn ends are engaged, are slightly tensioned for cutting and are conveyed by various means into the suction channel or conduit. For instance, mechanical yarn clamping, tensioning and end removing means have been proposed and used. However, such mechanical means have numerous drawbacks because they are complicated and must be operated at excessively low speeds.

In other known and used devices the yarns are urged towards the inlet of the discharge conduit and are temporarily tensioned solely by suction. This, however, obviously requires a substantial pressure gradient from a point upstream to a point downstream with respect to said conduit inlet and an air stream having a high enough flow rate and speed to cause the yarns to be attracted by suction while they are still outside the discharge conduit.

vThis has numerous disadvantages which substantially offset the advantage of the great simplicity of the device. For example, it is not always certain that the yarns will be attracted and tensioned as efiiciently as desired. The intensity of the air stream and the area of the yarn conduit inlet or inlets are such that all the upper part of the machine operates under a depression and the ambient air is caused to flow from all sides towards the dial cap. This causes dust and other solid particles suspended in the atmosphere to collect and accumulate on several delicate component parts of the machine. All these disadvantages are well known to persons skilled in the art.

Now, it is an object of this invention to provide a method for obtaining the useful effects of the known devices without their drawbacks, by engaging and entraining the yarns by mechanical means operated at a preferably constant speed and not subject to limitations as to the working rates of the machine.

More particularly, it is an object of the present invention to provide a method for engaging and removing yarn ends, as well as for facilitating the temporary tensioning of the yarns to be severed and at any rate for assuring their removal from the peripheral zone of the upper part of the machine. In particular this method permits the engagement and entrainment of the yarns to be cut, and the yarns that have been cut, at a point or zone. located between the location of the yarn feeding means and that of the yarn cutting means, the yarns being thus conveyed all the way to the inlet of a removal and discharge channel or passage, at least in part by means of an air stream.

It is another object of this invention to provide devices for the aforesaid purposes, in various constructive embodiments operating according to the aforesaid method.

Essentially, according to the invention the yarns are engaged and removed by an entraining action applied thereto at least at one point between the yarn feeding and the yarn cutting means. Said action is preferably mechanical and is effected by a member or members revolving or moving in a closed loop trajectory, the dial being possibly one of said members, and is augmented by pressurized air jets or streams operating at a point upstream of the discharge passage inlet. In producing said action, use is made of a state of adherence between the moving members and the yarns, in particular of a temporary state of adherence of said yarns to a surface moving in a continuous closed loop trajectory in succession through the yarn engaging zone and the vicinity of the removal channel. Such an adherence may be obtained by various means and is generally initiated and/or assured by pneumatic pressure produced by air jets. The engagement of the yarn with said movable surfaces may result from the superficial properties of these surfaces, and electrostatic charges, and/or adhesion phenomena, involving the use of weak non-drying adhesives, may also be exploited.

The motion of a surface as hereinbefore set forth, may be obtained by rotating a drumlet or an essentially cylindrical body, or a body shaped as any other suitable solid of revolution, the peripheral surface whereof is provided with the aforesaid adhering and entraining capacity; or it may be obtained by causing a small flexible belt to rev-olve in a closed loop over two or more guide rolls and/ or shaped sliding and guiding surfaces.

The revolution or closed loop motion of said surface may be obtained mechanically, as for instance, by transmission means operatively connected to members rotating in the upper part of the machine, or by applying the kinetic energy of the air jet or jets employed to cause the temporary adherence of the yarns to said surface or to detach the yarns from said surface at the clipped yarn ends discharge conduit or conduits inlets.

These and other features of the invention will be better understood by the following detailed description of various embodiments of the device according to the invention, hereinafter set forth by way of example and not of limitation, with reference to the attached drawings showing only the essential components of said embodiments that are characteristic of the invention.

In the drawings:

FIG. 1 shows in fragmentary plan view the upper portion of a circular knitting machine for fine knitted goods, typically for stockings, provided with a device comprising a rotating cylindrical surface for causing the temporary adherence and for mechanically conveying the yarns to the inlet of a discharge channel, and wherein the said temporary adherence and therefore the transfer of said yarns into said inlet, are obtained by means of air jets radially oriented from the outside to the inside and respectively from the inside to the outside of said surface;

FIG. 2 is a diametral section of the drumlet carrying said surface, said section being taken on the plane indicated at IIII in FIG. 3 wherein said drumlet is shown in a cross-section taken on the plane III-III of FIGURE 2;

FIG. 4 shows another embodiment of said drumlet, constructed and operated like a small turbine to cause it to be rotated by the air jets emitted for detaching and removing the yarns, said drumlet being shown partly in elevation and partly in cross-section in the direction and on the plane indicated at IVIV in FIG. 5, which illustrates the same in a cross-section taken on the plane V-V of FIG. 4;

FIG. 6, shows on a greater scale, partly in elevation and partly in cross-section, another embodiment of the drumlet device, including different means for causing the temporary adherence of the yarns to the rotating surface;

FIG. 7 is a fragmentary plan view, partially in section of the dial cap of the machine of FIG. 1, provided with a modified embodiment of the yarn engaging and removing device, in the form of a small flexible belt, so constructed and mounted as to be actuated in a closed loop motion;

FIG. 8 is a fragmentary sectional view of the device of FIG. 7, on the plane VIII-VIII of said FIG. 7; and

FIG. 9 is a cross-section of the upper part of the machine, including the dial and the dial cap, taken on the plane indicated at IXIX in FIG. 1, to illustrate an indicative positioning of said device, said positioning being subject to adaptations for the different embodiments of the same.

The device shown in FIG. 1, illustrates a practical application of the method according to the invention and the basic concepts of such an application. Therein numeral 10 indicates the cap of the rotating dial of the machine, at the periphery of which the yarns to be severed, for example those issuing from yarn feed fingers at the yarn feed station 12, are progressively advanced until they reach a known cutting means 14. These and the machine components hereinbefore referred to, are well known in the art and therefore will not be described in detail. To describe the invention, it is sufficient to point out that the yarns from station 12 that are to be severed are progressively carried by the periphery of the dial from a point adjacent station 12 to the cutting means 14in the direction indicated by the arrow A.

According to the invention, there is provided and used a revolving or circulating surface located and operating in such a position that said yarns may temporarily come into contact therewith and may be carried, due to a temporary condition of adherence thereto, to a position from which they begin to be conveyed to the discharge zone, for instance to a suitably shaped inlet 16 of a channel or chamber 18 connected at 20 to a vacuum discharge piping (not shown).

In the typical embodiment of FIG. 1, the surface with which the yarns are contacted and placed in a condition of a temporary adherence, is constituted by the outer surface 22 of a revolving body, for example a drumlet 24 having an essentially reticular surface and being largely air permeable, so that an air jet emitted for instance by a nozzle 26 fed with compressed air from pipe 28, may displace the yarns which appear before it, towards and against said surface 22.

The material of the body 24 which has the surface 22 may for instance be a porous fabric of pliable, semi-rigid or rigid reticular structure, permeable to air jets, whereby the yarns remain in adhering relationship to said surface to be carried by the same to a position facing inlet 16,

through which they are introduced into chamber 18 to be thereafter discharged.

The temporary adherence of the yarns on surface 22 may be promoted for instance by superficial hair formations, by the provision of small projections or other like means, and said material forming surface 22 may be for instance a sparsely textured velvet, a hairy reticular fabric or the like. Cylindrical reticular surfaces having an outer surface provided with pointed projections, such as those used for hair curlers for womens hair, or the like, may for example be used.

The yarns are carried along by the surface 22 as it continuously revolves in the direction B, and are detached therefrom at a position facing inlet 16 by mechanical means such as raking combs, or by the action of air jets directed from the inside to the outside of said surface 22 as schematically indicated by the arrows C in FIG. 6. The same jet emitted by nozzle 26, which diametrically traverses surface 22, may be used to cause or contribute to causing the yarns to be so detached or to be directed into said inlet 16.

As shown by way of example in FIGS. 2 and 3, reticular structure 24 having the surface 22, may for instance be mounted between flanges 30 and 32, forming with the same a drumlet which may be inserted in a replaceable manner on the lower end 34 of a rotating tubular shaft 36 (FIG. 9) mechanically actuated from the central drive shaft 40 of the machine, for example through a gear coupling 38. Said drumlet may be mounted around a hollow body 42 provided with a radial slit 44 forming a nozzle for an air jet for detaching the yarns and directing the same into the aforementioned inlet 16. Said jet may be fed with air under pressure from a pipe 46 (FIG- URES 2 and 9) located within the hollow shafts 36, and connected, for example, to the same air supply as pipe 28.

The rotating drumlet above described or an equivalent means may be driven by various means. As shown by way of example in FIGURES 4 and 5, said drumlet may be provided with a plurality of slanted blades 48 which are struck by the air jets issuing from the inner hollow body 42 and thus caused rapidly to rotate. Said jets may issue not from one slit nozzle 44 but from two or more slit nozzles 44' and 44", in such a way that at least one of said radial blades 48 be always struck by an air jet.

Should it be troublesome or in any way difficult to mount a nozzle 26 outside the periphery of the dial, solutions such as that shown by way of example in FIG. 6 may be adopted.

The rotating drumlet, substantially as hereinbefore described or constructed in any other suitable way, may be surrounded by a plurality of deflector rings 50 which deviate one or more air jets 52 emitted by one or more nozzles 54 placed substantially above said drumlet and impart to said jet or jets a substantially radial direction with respect to said drumlet, so that they traverse the same and issue therefrom in the direction shown by arrows C.

Said drumlet may be mechanically driven by a rotating shaft or may be actuated pneumatically, as respectively described with reference to FIGURES 2 and 3 or FIG- URES 4 and 5.

The upper flange of the drumlet may be solid with helical blades (not shown) which at least in part intersect the said jet or said jets 52.

Deflector rings 50 may be so shaped as to constitute blades which lead the yarns towards the entraining surface 22, and they may be flattened, as indicated at 50', on the side of the drumlet from which the yarns are to be detached from their temporary adhering relationship to surface 22.

Obviously, according to the particular knitting machine used, one or more rotating drumlet devices may be adopted, in correspondence to the inlets of the various yarn conveying and discharging passages, particularly in machines having a plurality of yarn feeds and of cutting devices spaced at the periphery of the dial. If it were convenient or desirable that the surface to which the yarns temporarily adhere and by which they are entrained should possess a greater extension along the periphery of the dial, said surface instead of rotating may have a circuital or closed loop revolving motion involving a longer trajectory in the zone in which it can engage the yarns.

As shown by way of example in FIGS. 7 and 8, surface 22' may be materially constituted by the outer face of a reticular flexible material 24' disposed as a ribbon or conveyor belt circulating over at least two rotating members 56 and 58, at least one of which may be driving, and between which a shaped body 60 may be disposed having a cavity 62, connected at 64 to a compressed air source and provided with a slit nozzle 66 so oriented as to cause the yarns to become detached from said surface 22' and to be directed into inlet 16' of discharge conduit 18'.

Obviously the positions of the components of the device depend on the space available and/ or on the location of the various devices on the upper portion of the knitting machine.

FIGURE 9 is an example of such positioning, referred to the embodiments of FIGS. l-3. Of course, the relative positions and the structure of the various rotating, feeding, blowing and other means, will be predetermined taking into account the specific construction of the knitting machine.

Obviously also, if necessary, the pressure air to nozzle 26 and slit nozzle 44 or 66 may be stopped when a severed inactive yarn has been satisfactorily engaged by suction mount 18 or 18. Advancement of drumlet 24 by, for example, gear coupling 38, is not in itself sufficient to withdraw additional yarn through an inactive yarn finger.

From what has been set forth hereinbefore, it will be evident that the method and the device according to the invention have considerable advantages and valuable technical elfects. Since no use is made of a strong vacuum to attract the yarns from their natural positions to the inlets of the discharge passage or passages, as is done in certain known systems, this invention avoids the very serious draw-backs represented by the continuous attraction and accumulation of atmospheric dust and of the textile fibres and other solid material that may be present in the room atmosphere, on the delicate component devices of the machine, particularly on the needle cylinder and on the dial. Further, in said known devices the yarn entraining action may be too weak at a certain distance from the inlet or inlets, since it is obviously impossible to increase the suction beyond a certain limit and the speed of the air streams conveiging towards the inlets from various directions sharply drops even at a few millimeters distance from said'inlets and becomes insufficient for a positive entraining action: this drawback too is completely avoided by this invention. By comparison with devices including members having 'an alternating motion and/or having strictly localized clamping points, the devices according to the invention have important advantages, be- 1 cause they afford much higher operating speeds and a much wider flexibility and latitude of choice in engaging and conveying th e'yarns.

It will be obvious to persons skilled in the art that many modifications and adaptations may be made in the embodiments of the invention as hereinbefore described and that different embodiments may be devised without departing from the invention or exceeding the scope of the appended claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. The method for facilitating the tensioning, severing and discharging of yarn end portions in a circular knitting machine, which has a needle cylinder, a dial adjacent to the top of said cylinder, and duct means for holding yarn ends having an inlet above said dial, comprising providing a member located above said dial and having an outer surface adapted to frictionally engage a yarn located in tangential relationship therewith,

arranging said member so that a zone of said outer surface thereof is tangentially contacted by yarns engaged and displaced 'by said dial,

actuating said member to move said outer surface thereof in a closed looped path progressing towards said inlet at said zone, and

projecting a stream of pressurized gas at said zone transversely of said path and of yarns travelling along said path.

2. The method defined in claim 1, wherein said member has an outer, essentially cylindrical surface, and said member is rotated about the axis of said surface.

3. The method of claim 2 wherein said outer surface is a perforated outer wall of said member, and

directing a gaseous stream from inside said wall and through said wall towards said inlet, to disengage said yarns from said surface.

4. In a circular knitting machine having a rotary needle cylinder, a dial located and driven for rotation adjacent the top of said cylinder, a stationary dial cap, at least one yarn feed station arranged adjacent said dial for selectively feeding individual yarns thereto, and duct means for receiving severed yarn ends, and having an inlet above said dial cap, a yarn tensioning and discharge facilitating device comprising a member mounted for motion in a closed loop path including a zone at which a yarn end extended between said station and said inlet is tangentially engaged on said member,

said member having an outer surface adapted for pro viding adherence with said tangentially engaged yarn,

means for actuating said member to move said outer surface thereof toward said inlet in said zone, and nozzle means for directing gas under pressure toward said surface to urge said yarn ends thereagainst.

5. The device of claim 4, wherein said member has a cylindrical outer surface and is supported for rotation about the axis of said surface, said axis being essentially parallel to the axis of said dial.

6. The device of claim 5, wherein second nozzle means is located inside said surface, and is directed towards said inlet.

7. The device of claim 5, wherein said nozzle means is located outside said surface and is directed at said surface for causing said gaseous stream to impinge on said sur face where tangentially contacted by the yarns.

8. A device as defined in claim 5, wherein said member comprises a cylindrical, screen-like Wall,

the outside of which defines said outer surface,

tunbinelike vanes are supported within said wall,

said member is rotatably mounted on a stationary, hollow body having second nozzle means formed therein, and

means connects the interior of said body to a source of pressurized gas that is directed by said second nozzle means onto said vanes to impart rotation to said member.

9. The device of claim 4, wherein said surface is formed by the outer face of a metallic screen.

10. The device of claim 4, wherein said surface is formed by the outer face of a sparsely textured velvet.

11. The device of claim 4, wherein said member comprises a belt-like component supported and driven for 7 8 13. A device as defined in claim 7, wherein 3,164,975 1/1965 Haberhaver 66140 XR said nozzle means is located above said dial, and is 3,174,307 3/1965 Mayer 66-134 positioned to direct said stream toward said dial, and 3,197,977 8/ 1965 Stack 66-140 means is positioned between said member and said 3,257,829 6/1966 Parthum 66-134 nozzle means to deflect said stream radially toward 5 3,283,544 11/1966 Kent 66140 and onto said surface. 2,908,154 10/ 1959 Butler 66-140 References Cited FOREIGN ENTS UNITED STATES PATENTS 646,803 10/1962 Italy- 3,075,374 1/1963 St. Pierre 66-145 10 WM. CARTER REYNOLDS, Primary Examiner. 

